Process of producing ammonia.



UNITED srarns PATENT OFFICE.

CARL BOSCH, OF LUDWIGSHAFEN-ON-THE-RHINE, GERMANY, ASSI GNOR T BADISCHE ANILIN & SODA FABRIK, OF LUDWIGSHAFEN-ON-THE-RHINE, GERMANY, A COR- PORATION.

PROCESS OF PRODUCING AMMONIA.

990,191. Specification of Letters Patent.

No Drawing.

To all whom it may concern:

. Be it known that I, CARL Boson, doctor of philosophy and chemist, subject of the King of Prussia, residing at Ludwigslia'tenon-the-Rhine, Germany, have invented new and useful Improvements in Processes of Producing Ammonia, of which the following is a specification.

My invention @relates to the production of ammonia from the so-called titanium cyanonitrid, which can easily be obtained for instance by heating a mixture of titanic acid and carbon in the presence of nitrogen (Deville and Wiihler, Annalm'llcr ("her/tie, vol. 103, p. 230 ct ear n).

It is stated in the literature on the subject that titanium cyanonitrid is unattacked by boiling concentrated sulfuric acid and that by melting it at a red heat with potassium bisulfate (/1 nuclei). (Zcr (Uremic, 73, p. 38) the nitrogen is evolved as such, and it is also stated (Dammer Handbuck d. anozg. Ohemz'e, II, part 1, page 591) to be soluble in a mixture of nitric acid and hydrofluoric acid. In this case also nitro" en is set free. On the other hand, by me ting titanium cyanonitrid with caustic alkali, or bypassing steam over it at a red heat, ammonia is obta'incd, but these reactions are not suitable for carrying out on a large scale since the first reaction is too costly and the second reaction does not yield suiiicient ammonia.

I have now discovered that titanium cyanonitrid can be made to yield ammonia in a manner which allows the reaction to be carried out on a commercial scale by oxidizing it-under such conditions that none, or practically none, of the ammonia iorlncd becomes further oxidized to free nitrogen. Provided that this condition be maintained, many different oxidation agents and methods may be employed, for instance the reaction'can be carried out in alkaline,'or neutral, or acid solution, or suspension, or even in a melt. In all cases of course some body containing hydrogen such for instance as water, or steam, or sulfuric acid, must be present; As examples of oxidizing agents I mention chromic acid, manganese dioxid, iron oxid, copper oxid, cerium oxid, mer- Patented Apr. 18,1911.

Application filed March 2, 1908. Serial No, 418,848.

cury oxid, and salts correspondingto these oxids. The oxidation may also be caused to hate place by treating the titanium cyanonitrid with steam in the presence of an oxid or hydroxid'or salt oil an alkali or alkaline earth metal (such, for instance, as sodium carbonate, caustic soda, and calciumchlorid) \viich, by itself, under the conditions used as to temperature and quantity, has no oxidizing action, or practically no oxidizing action, on the titanium compound but which in the presence of steam favors the oxidation. Steam by itself does not react upon titanium cyanonitrid until such a temperature is reached that the ammonia formed is decomposed again to a greater or lesser extent. Or the oxidation may be carried out by hcatim; the titanium cyauonilrid with a hisull'ate, provided the temperature employed be not too high, and by boiling it with concentrated sulfuric acid. If desired, the treatment with sulfuric acid or with a bisulfate can be caused to take place in the presence of water and under pressure. Electrolysis with or Without the use ol so-callcd oxygen carriers can also be easily be rcconvcrt ed into titanium cyanonitrid making use of atmosphere nitrogen.

If, when carrying, out the oxidation in the presence of air and steam as hercinbefore described, a contact body, such for instance as finely divided platinum be present the ammonia produced is wholly or partially oxidized to oxids of nitrogen.

During the reaction which takes place according: to this invention, the titanium cyanonitrid is oxidized so that the nitrogen is converted into ammonia, the titanium is converted into titanic acid (TiO and the carbon either remains as such, or it may be oxidized according to the vigor with which the oxidizing agent acts. For instance if oxidizing boiling sulfuric acid be employed as the agent. the carbon is converted into carbon dioxid. Of course if the oxidiz ing agent capable of combining with the ammonia formed or with the titanic acid, this will lead to the formation of salts. Thus, when'boili'ng sulfuric acid is employed for oxidizing purposes according to this invention, the ammonia is obtained in the form of ammonium sulfate and the titanium oxid will also combine with sulfuric acid to form titanium sulfate. On the other hand if the titanium cyanonitrid be treated with caustic soda solution and copper oxid, the ammonia is produced in the free form, while the copper oxid is reduced. When titanium cyan-onitrid is heated with sodium carbonate in the presence of steam, ammonia is produced, generally partly as such and partly in the form of ammonium carbonate while the titanium is obtained in the form of titanium oxid or sodium titanate, and some hydrogen and some carbon monoxid are also formed. On the other hand, when titanium cyanonitrid is heated with platinum chlorid in thepresence of air and steam, ammonia is presence of the platinum is partially oxidized into nitric oxid, while the titanium is converted into titanium oxid and the carbon is oxidized .to carbon dioxid.

The following examples will serve to illustrate further the nature of my invention, which, however, is not confined to these examples. The parts are by weight and the temperatures in degrees *centigrade.

Example 1 Boil 1 part of titanium cyanonitrid with 10 parts of concentrated sulfuric acid. Sulfur dioxid is evolved and in from '15 to'30 minutes the oxidation is complete. The nitrogen of the titanium cyanonitrid has been converted into ammonium sulfate. which can be worked up in any desired manner.

Example 2: Melt 1 part of finely divided titanium 'cyanonitrid with 5 parts of potassimn bisulfate at from 300 to 400 degrees. After from 30 to 0 minutes, dissolve the I melt in water, digest. for a considerable time at. 100 degrees, until the titanic acid has separated out, filter. add exce s of lime to the filtrate, and drive oil the ammonia by means of heat.

Exan'i tile 3: Heat together in an autoclave,

for from 2 to 3 hours, at :if temperature of from 350 to 400 degrees, 1 part of finely dividcd titanium cvanonitrid, 3 part of-so: dium bisulfatc, and 3parl's of water, and

\rorh up the product as described in the foregoing Example .3.

'llxam'ple l: lleat together, in an auto clave, at. about 180 degrees, finely divided titanium cyanonitrid, 30 per cent. caustic formed and in the.

soda solution and suliicient copper oxid t0 ctfect oxidation. ,On opening the valve of the autoclave ammonia escapes. ample instead of copper oxid, an equivalent quantity of ironoxid or manganese peroxid 'or' chromic acid can be employed.

.l lxample 5: Heat together, for from 2 to 3 hours, on the water bath, titanium cyano- In this exnitrid and ferric sulfate solution. Ferrous sulfate is formed and the solution also contains ammonia. p Example. 0: Heat together at from 100 to 1-1-0 degrees, in an autoclave, titammn cyanonitrid, dilute sulfuric acid rous sulfate solution, and pump in air, while stirring well, until the oxidation is complete. I f the ferrous sulfate be omitted, the

I reaction proceeds more slowly.

Example 7: Suspend titanium cyanoniind in dilute sulfuric acid, add some chrominm sulfate, or ferrous sulfate, 'to the suspension and oxidize it electrolytically at 100 and a little ferdegrces,' in a cell provided with a diaphragm Example 8: Heat a mixture of 1 part of titanium cyanonitrid with 3 parts of sodium carbonateiii a current of steam at a temperature of from 400 to 500 degrees. Ammonia passes over either in the free state or in the form of its carbonate.

Example 9: Heat a-mixture of 2 parts. of titanium cyanonitrid with 1 part of caustic soda in a current of steam at a temperature of from 300 to 400 degrees. In a short time the evolution of ammonia is complete.

Example 10: Soak. titanium cyanonitrid in platinum chlorid solution until it contains from 2 to 3 parts per 1,000 of platinum and thenheat it at from 300 to 400 degrees in a current of mixed air and steam. By.

ence of as body containing hydrogen while maintaining the tcn'iperaturc so low thatthe production of free. nitrogen is practically avoided.

.2. The process of producing ammonia by heating titanium cyanonitrid 'With an oxidining agent in the preser e of a body'containiug hydrogen while maintaining the temperature so low that the production of "free nitrogen is practically avoided.

I). The process of producing" an'n'nonia by heating titanium cyanonitrid 'with an oxidizing agent. in the presence of an oxid or hydroxid or salt of earth metal and in the. presence of a body containing hydrogen.

an alkali or alkaline l. The process of producing ammonia by In testimony whereof I have hereunto set heating titanium cyanonitrid with air and my hand in the presence of two subscribsteam in the presence of an oxicl or hydroxid ing witnesses. or salt of an alkalior alkaline earth metal. CARL BOSCH.

5' The process of producing annnonia by Witnesses:

heating titanium cyanonitrid with air in the J. Amw. LLOYD, presence of ferric sulfate and water. J os. H. LEUTE. 

